The ceremony of trooping the colour, which will take place on June 12 in celebration of the King's birthday was rehearsed on the Horse Guards Parade today. The parade, which dates from the 18th century, has not been held since before the war, when, with the guards resplendent in full dress uniforms, it was one of London's most colourful ceremonies. This year, however, battledress and service dress will be worn. Her Royal Highness Princess Elizabeth, so whom it is the first trooping of the colour since she was made Col of the Grenadier guards, will ride with the King when the ceremony takes place. 5 June 1947